I believe the monkey gland is called that because around the time it was invented there was a surgeon (Serge Voronoff) who was promoting a surgery in which he would implant baboon testicles into men (there was a corresponding surgery for women as well). It was supposed to improve the libido. An early, probably ineffective form of hormone replacement therapy.

There is even a wikipedia page on it: https://en.wikipedia.org/wiki/Monkey_gland

Which still sounds super fake to me. It takes a host of modern drugs to prevent rejection when doing human-to-human transplants. I have long odds that monkey tissue would result in anything but a painful, septic death.

As a medical benchmark, penicillin was discovered in 1928.

Edit: I was ignoring the obvious - sham surgery! Just leave a bit of a scar, maybe inject them with some cocaine, and everyone comes out smiling.